The present invention deals with the problems of persons performing the task of removing at least one section of an object having a meeting surface which may consist of material such as dry wall, wood grain, masonite and other types of paneling, tiles, carpeting and the padding therefore, wood fabrics, clothes, etc. to be installed on an existing surface embodying first materials such as vents for air conditioning and/or heater units, electrical convenience receptacles or the like, windows, doors, etc. to allow said first materials to perform their functions after the installation of said object having a meeting surface. These persons must devote a substantial amount of time in measuring and employ some sort of straight-edge device to find and establish the correct pattern of the first material, which then must be transposed to the object having a meeting surface to define at least one section of the latter that must be removed to allow said first material to perform its above-indicated function. Some problems which occur in such installation process result from human error, such as, for example, when a single measurement is not correct or if the measurement is correct, the person transposing that measurement to the object having a meeting surface makes an error. If an error is not corrected before any removal of the unwanted sections of said material according to the aforesaid pattern, this could destroy the usefulness of said object having a meeting surface and prevent it from being permanently installed, thus possibly wasting that object, money, time, etc.